FROM time to time, I reflect upon the articles I have written for this column and feel I need to bring readers up to date about continuous advances in research techniques in the fields of scientific and environmental sciences. In retirement, I am privileged to have the time to read journals and the world’s press and, moreover, to update my knowledge. Here are but a few that may interest regular readers of this column.
World’s oldest footprints
A joint Chinese and American team has discovered what is likely to be the earliest records of arthropod tracks in uplifted mudstone/shale rocks in the gorges of the Yangtze River in China. Arthropods, such as spiders and other insects as well as millipedes and centipedes, have segmented bodies with jointed limbs. These footprints suggest that, 500 million years ago, this creature had poorly coordinated limbs which trod out an irregular pattern of movement, unlike the present rhythmic patterns of today’s arthropods.
Apes and first humans
A link between apes and the first humans was first recorded in 2000 with the discovery of a child’s skeleton at Dikka, in the Afar region of northern Ethiopia. Upon recent further examinations of the child’s 5cm-long foot, discoveries have been made as to how she walked, as a two-and-half-year-old, 3.3 million years ago. With a low arch and large heel bone, she walked on both legs but her big toe’s structure is more like that of a chimpanzee and thus she was able to cling on to tree branches. This implies that at night the child could easily escape if threatened by wild animals by climbing the nearest tree, or in day time could enjoy the tree’s fruits.
Coral reef threats and saviours
Surveying 1,800 coral reefs around the Chagos islands, the Maldives, the Seychelles, Papua New Guinea, and inevitably the Australian Great Barrier Reef, to include so-called marine reserves, marine biologists have concluded that overfishing has led to a decline in shark populations. Sharks were distinctly absent from 70 per cent of the reefs observed. The conclusion of these scientists’ report suggests that in very remote marine reserves where human pressures were low, four times more sharks were observed on coral reefs than in the reserves where humans were present in greater numbers and thus highly fished. Sharks prevent any species of larger fish from dominating reefs, thus allowing smaller herbivorous species to thrive on the algae, which attempt to overwhelm young corals. Having snorkelled over coral reefs in Sabahan and Kenyan waters, I have always been the first up the ladder of the boat upon spotting a shark. Little did I know, until now, that sharks are the keepers of coral reefs.
From the same extensive survey, it has been found that land rats are damaging tropical island coral reefs, by depriving corals of the nutrients provided in guano or bird droppings washed off the shores into the sea. Most rats found on tropical islands are invasive species that have literally jumped a visiting ship at anchor. From their feeding on bird’s eggs, chicks and even adult birds, the bird population falls and the guano-rich nitrogen and phosphorous thus decline.
In diluted form in seawater, these chemicals promote the growth of algae and sponges on fringing reefs, which in turn provide grazing grounds for huge numbers of small herbivorous fish. In the Chagos Islands, in the mid-Indian Ocean, the marine ecologists found the density of seabirds some 760 times greater than on infested islands. Kill the rats and at the end of the food chain protect the corals.
Can you remember the 2000 film called ‘The Beach’, starring Leonardo DiCaprio, filmed on Maya Beach in Thailand? This film prompted tourism at the daily rate of 5,000 visitors, thus causing an ecological tragedy. As the result of boat anchors, propeller churnings, oil, dropped litter, and the tourists’ theft of corals, 90 per cent of the coral reef there has died. Recovery operations are underway as the beach remains closed to tourists this year until next month to allow the coral reef rehabilitation procedures to take place. These have included the replanting of corals and the creation of offshore designated floating piers at which boats may moor. Tourist numbers have been reduced to no more than 2,000 per day. Such schemes have worked well in other similar threatened coastal areas of Thailand.
Northern white rhino
It was with great sadness that I reported in April this year of the passing of Sudan, the last male northern white rhino. His female companions, Najin and Fanu, could no longer bear any offspring. Upon his death, 200ml of Sudan’s semen was frozen and sent to the Leibnitz Institute for Zoo and Wildlife Research in Berlin. The geneticists there believe that they have found a way to take the skin from dead animals to create eggs to transplant into similar species. Sudan’s semen will be used to fertilise eggs taken from his female companions’ ovaries to implant into surrogate female southern white rhinos. These scientists anticipate that a northern white rhino calf could be born, after a gestation period of 16 months, as early as 2021. This technique, if successful, could be applied to other mammals on the brink of extinction.
Invasive Southeast Asian hornet
This yellow-legged hornet has advanced throughout Europe at an annual rate of 70km and in thus doing has wiped out 33 per cent of honey bee colonies along its path northwards. This has resulted in total annual losses of honey production and sales amounting to over RM54 million. Hovering outside beehives, they grasp bees hawk-like, rip them apart, and take the dismembered bodies to their huge nests to feed their larvae.
It is forecast that within the next decade, there will be over 50,000 hornets’ nests in England and Wales alone.
With funding from the British Beekeepers Association together with government funding, applied research ecologists at Exeter University purchased radio tags and carefully, using sewing thread, attached them to some captured hornets’ abdomens. Once released these hornets returned to their nests. This experiment was conducted near Bordeaux in France and again in the Channel Islands. The nests were tracked down within hours and quickly destroyed. Normally such nests would take five days to locate. To date, 80 per cent of French bee colonies have been destroyed by the hornets.
Tracing hornets’ nests early in the season not only allows more bee honey to be produced, but also prevents the spread of hundreds of queen hornets in each nest. Once they have emerged, they disperse and establish new nests. Interestingly, this summer in Somerset I have seen hundreds of bees on my lavender bushes with only a few hornets hovering. Two years ago, these invasive, destructive Southeast Asian hornets arrived in my county, having spread from France. This year, for the first time, they have been spotted as far north as Lancashire.
Genetic research and bio-technology have progressed in leaps and bounds to ecological advantage.
As football pundits would say, governments must be ‘on the ball’ in finding the wherewithal to fund environmental projects in specialist institutes and university research centres in their respective countries. To be forewarned is to be armed.